Building regulations for damp and mold in the UK cover the following key areas:
Building regulations for managing condensation in the UK include the following:
The 2021 revision of the Part F Building Regulations is slated to come into force on the 15th of June, 2022.
Approved Document F stipulates the prerequisites for ventilation within both residential properties and structures other than dwellings. This guideline is divided into two distinct volumes, with the official versions of these Approved Documents accessible on the Government’s website as referenced below:
The provisions outlined in Part F are intrinsically interwoven with those in Part L (concerning the conservation of energy and fuel), as both are being upgraded to align with the Government’s Future Homes Standard.
A pivotal method for enhancing energy efficiency is through diminishing thermal dissipation via air permeability, which necessitates constructing edifices with greater airtightness. Yet, this heightened airtightness inversely affects natural airflow, thereby necessitating the update of Part F to guarantee adequate ventilation levels are consistently upheld.
Outlined below are salient distinctions and consistencies between the existing 2013 Part F Approved Documents and the revamped 2021 edition.
The stipulated extract rates for intermittent systems persist unchanged within the 2021 iteration of the Part F Approved Document. Kitchens will still mandate an extract rate of 30 l/s if positioned adjacent to the hob, or 60 l/s when situated elsewhere. Utility rooms will continue to necessitate 30 l/s, bathrooms 15 l/s, and lavatories 6 l/s.
The requisite baseline rates for continuous extraction likewise remain static under the 2021 guidelines. Specifically, kitchens will require a steady rate of 13 l/s, utility rooms and bathrooms 8 l/s, and toilets will still demand 6 l/s. Moreover, the cumulative extract ventilation rate, referred to as the minimum low rate, must satisfactorily align with the designated whole dwelling ventilation standard.
While the directive to satisfy the whole dwelling ventilation thresholds is a constant in both the former and the latest Part F Documents, the actual specified rates have been revised under the new guidelines.
Under the updated 2021 Part F Approved Document, using intermittent extract fans along with natural ventilation through background ventilators is now only recommended for homes with lower airtightness. These are homes designed with an air permeability greater than 5 m³/(h.m²).
However, because of the new Part L Building Regulations, achieving such a high air permeability would make it very challenging to meet the required carbon reduction targets. As a result, most newly designed homes are expected to be classified as highly airtight, with air permeability levels below 5 m³/(h.m²).
That said, if a home is classified as having lower airtightness, the minimum required equivalent area for background ventilators has been updated in the 2021 Part F Approved Document.
Previously, under the current Part F document, the minimum ventilator area was determined by the home’s total floor space and number of bedrooms.
In contrast, under the new 2021 Part F Approved Document, the minimum required area for background ventilators is now determined on a room-by-room basis.
For continuous mechanical extract systems, the current Part F mandates a minimum equivalent area of 2,500 mm² to be installed in each habitable room, excluding wet rooms. Under the new 2021 Part F Approved Document, this requirement has been increased to 4,000 mm².
The requirements for purge ventilation remain largely unchanged between the two documents.
A purge ventilation rate of at least 4 air changes per hour, directly venting to the outside, is still necessary. This can be achieved by using hinged or pivot windows with an opening angle between 15 to 30 degrees, ensuring a minimum open area that equals at least one-tenth of the room’s floor area.
If the window opening angle exceeds 30 degrees, then the minimum total open area can be reduced to one-twentieth of the room’s floor area
Purge ventilation rates can also be achieved through mechanical systems if needed. While 4 air changes per hour is the minimum required rate, higher ventilation rates may be necessary to comply with the new overheating requirements outlined in Part O of the Building Regulations.
The ventilation requirements for offices, as outlined in the new 2021 Part F Approved Document, remain mostly the same.
Toilets still require an extract rate of 6 l/s per WC or urinal, while showers or baths continue to need a 15 l/s extract. For kitchen areas, the requirement is still 15 l/s when only a microwave is present, and 30 to 60 l/s when a cooker is in use, depending on whether the extractor fan is located close to the cooker or not.
On the supply ventilation side, the required fresh air rate remains at 10 l/s per person. However, the new regulations now also mandate providing at least 1 l/s per m² of floor area, with the higher of these two rates to be used.
Common areas such as corridors or lift lobbies require either natural ventilation openings equal to at least one-fiftieth of the floor area or, if using mechanical ventilation, a minimum rate of 0.5 l/s per m² of floor area.
There are a few other minor adjustments between the existing 2013 Part F Approved Documents and the new 2021 version that may be worth exploring, but we have focused on the key changes in this article for easy reference.
The new Part F Regulations will come into effect on 15th June 2022, meaning any developments seeking planning permission after this date will need to comply with the updated guidelines.
If you require a ventilation design that adheres to either the current 2013 Part F Approved Document or the new 2021 version, please reach out to us using the contact details provided below.
UK building regulations for winter heating include the following key provisions:
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